Degradation mechanism of glass fiber/vinylester-based composite materials under accelerated and natural aging

Degradation mechanism of glass fiber/vinylester-based composite materials under accelerated and natural aging

Glass Fiber Reinforced Polymers (GFRP) composites have become the materials of interest in replacing steel, wood, and concrete in building and construction. However, limited understanding of degradation mechanisms under physical and chemical aging of GFRP composites is still a concern preventing the widespread implementation and use of this new and emerging material in civil infrastructure. In this work, accelerated aging data for GFRP vinyl-ester composites conditioned at varying pH (2 to 13) and temperature (−22 °C to 71 °C) were collected from laboratory testing and from literature, and compared with the natural aging data under natural environment. It focuses on interlaminar shear strength (ILSS) as this is the most significantly affected property when composites are exposed to aggressive environments. High pH environment and high temperature are found to be most detrimental to GFRP composites where loss in ILSS of up to 30% was measured within the first 80 to 100 days of aging. Arrhenius model and time shift factors were used to correlate the accelerated aging data to the degradation of composites in a neutral pH environment under natural conditions. The correlation between field (natural) and accelerated aging data showed that 30% degradation of ILSS in composites occurs within the first 3 to 10 years of service, followed by a more gradual decrease. Service knock-down factors were then established in order to take into consideration the environmental and chemical effects surrounding the design of GFRP composites over a 100-year service life.